When to discard bad eggs?

I'm on day 8 and have only been able to candle 1 white egg and find a living embryo. The others are 2 banty white (saw nothing, thinking they are not fertile) and the other 8 eggs are dark brown. I'm planning to get a better flashlight and attempt it again. I'm new to candling and hate the thought of removing bad eggs if I have read them wrong. When is a good time to assume the egg is not developing and discard it? How risky is it to let the bad eggs stay?

I've had loads of infertile eggs, loads of embryos that have died in the first ten days, and loads of fully formed chickss that have died in the shell without pipping. But I've never had a bad egg yet. Duds aren't dangerous to leave in, and from what I've read, the smell of a truly bad egg is unmissable. If you're new to candling and you don't smell anything bad, I'd say leave them ALL in. You don't want to chuck out a viable egg by mistake...

Quote:Very interesting! We have a few under a broody right now. She started with 9 and we are down to 5. So far we've been correct on infertile/bad eggs. We cracked them once we felt really sure they were not developing. They've all just been white & yolk. I admit though, I'm a little nervous each time. We're learning though, so I won't be too hard on myself if we make a mistake. I thought I had read with my Brinsea info that the most reliable way to know is to weigh the eggs. Fertile eggs will get lighter.